（1） All night long： 整夜 Some stores stay open all night long.
（2） Call it a day： 一天工作完毕 We have class from 9am and will call it a day at 4.30pm.
（3） Day after day： 每天 It is boring to do the same things in school day after day.
（4）Day in day out： 一天又一天 Henry wears the same old jeans day in day out.
（5）For a rainy day： 为困难的日子作准备 When a person gets older, he will realize the importance of saving for a rainy day.
（6）In this day and age： 在现在这时代 In this day and age, no one can expect to get something out of nothing.
（7）Have an off day： 不大成功或顺利的一天
Tom did not do well in yesterday's test. He considered him unlucky enough to have an offday.
（8）The order of the day： 一般的惯例
In a petroleum station here, payment by credit card is the order of the day.
（9）The other day： 几天前 I bumped into an old friend the other day.
（10）To this day： （指日期）准确地 It is 40 years to this day that I left university.
（11）Have seen better days： 曾经历过好日子
Jack was an office head in that university before he came here. He has seen better days.
（12）Some day： 将来 Everyone hopes to be great some day.
（13） One's days are numbered： 末日将临：
Under computerization, unskilled workers become redundant. Their days in a company arenumbered.